　ナイロン糸で試作したガラス化用具を用いて，拡張胚盤胞期のウシ体外受精胚を材料として超急速ガラス化し，保存後の生存性および発育性を緩慢冷却法と比較検討した。その結果，超急速ガラス化で保存した胚は，緩慢冷却で保存した場合より有意に生存率，透明帯脱出率が高かった。さらに，超急速ガラス化法で用いたガラス化液間の比較では，GESX（20％グリセロール，20％エチレングリコール，0.3Mシュクロース，0.3Mキシロースおよび3％ポリエチレングリコールを添加したリン酸緩衝液のガラス化液）が，糖類を含まないガラス化液ED（20％エチレングリコール，20％ジメチルスルホキシドおよび20％仔ウシ血清を添加したTCM199）より，生存性および発育性が良好であった。これらのことから，ナイロン糸を加工したガラス化用具は，ウシ体外受精胚にとって有効であることが示唆された。

Survivability of Vitrified Bovine Embryos Produced in Vitro Using Nylon Thread. KASA Shojiro, Miyuki MORI and Syuji UEDA(Fukuoka Agricultural Research Center, Chikushino, Fukuoka 818-8549, Japan)Bull. Fukuoka. Agric. Res. Cent 24:68-72 (2005)

　An experimental bovine embryo vitrification tool was made using nylon thread. Bovine expanded blastocysts produced in vitro were vitrified by a rapid cooling method using the tool. A comparative examination on survivability and growth after preservation was carried out with a slow cooling method. Rapid cooling resulted in significantly higher rates of survival and hatched zona pellucida compared to the slow cooling method. Moreover, the survivability and rate of growth of embryos with the vitrification solution GESX (20% glycerol, 20% ethylene glycol, 0.3M sucrose, 0.3M xylose, 3% polyethylene glycol in D-PBS ) was better than the vitrification solution ED (20% ethylene glycol, 20% dimethylsulphoxide, 20% calf serum in TCM-199 ) which did not contain sugar. The results indicated that bovine embryos produced in vitro and given the rapid cooling treatment with the tool were able to maintain survivability at a higher rate compared with the slow cooling method. Moreover, the tool, which was made of nylon thread also served as an effective container for vitrified bovine embryos.